Systems and methods for visualizing and directing stimulation of neural elements

ABSTRACT

Method and systems for determining a set of stimulation parameters for an implantable stimulation device include receiving a set of stimulation parameters including at least one electrode for delivery of stimulation and a stimulation amplitude for each electrode; determining, using the set of stimulation parameters, an axial stimulation field for neural elements oriented axially with respect to a longitudinal axis of the lead; and outputting the first axial stimulation field for viewing by a user; receiving, by the computer processor. The methods and systems can be used to model other neural elements oriented non-orthogonally with respect to the longitudinal axis of the lead and determine a non-orthogonal stimulation field.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. §119(e) of U.S.Provisional Patent Application Ser. No. 62/383,200, filed Sep. 2, 2016,which is incorporated herein by reference.

FIELD

The invention is directed to the area of electrical stimulation systems.The present invention is also directed to systems and methods forvisualizing and directing electrical stimulation of neural elements, aswell as methods of making and using systems.

BACKGROUND

Electrical stimulation can be useful for treating a variety ofconditions. Deep brain stimulation can be useful for treating, forexample, Parkinson's disease, dystonia, essential tremor, chronic pain,Huntington's disease, levodopa-induced dyskinesias and rigidity,bradykinesia, epilepsy and seizures, eating disorders, and mooddisorders. Typically, a lead with a stimulating electrode at or near atip of the lead provides the stimulation to target neurons in the brain.Magnetic resonance imaging (“MRI”) or computerized tomography (“CT”)scans can provide a starting point for determining where the stimulatingelectrode should be positioned to provide the desired stimulus to thetarget neurons.

After the lead is implanted into a patient's brain, electrical stimuluscurrent can be delivered through selected electrodes on the lead tostimulate target neurons in the brain. The electrodes can be formed intorings or segments disposed on a distal portion of the lead. The stimuluscurrent projects from the electrodes. Using segmented electrodes canprovide directionality to the stimulus current and permit a clinician tosteer the current to a desired direction and stimulation field.

BRIEF SUMMARY

One embodiment is a computer-implemented method for determining a set ofstimulation parameters for an electrical stimulation lead. The methodincludes receiving, by a computer processor, a set of stimulationparameters including at least one electrode for delivery of stimulationand a stimulation amplitude for each electrode; determining, by thecomputer processor and using the set of stimulation parameters, a firstaxial stimulation field for neural elements oriented axially withrespect to a longitudinal axis of the lead; and outputting, by thecomputer processor, the first axial stimulation field for viewing by auser. The method may also include receiving, by the computer processor,a modification of the set of stimulation parameters; determining, by thecomputer processor and using the modified set of stimulation parameters,a second axial stimulation field for neural elements oriented axiallywith respect to a longitudinal axis of the lead; outputting, by thecomputer processor, the second axial stimulation field for viewing by auser; receiving, by the computer processor, a selection of either theset of stimulation parameters or the modified set of stimulationparameters as a selected set of stimulation parameters; and outputting,by the computer processor, the selected set of stimulation parameters tobe received by an electrical stimulation device for delivery ofelectrical stimulation to a patient via an electrical stimulation lead.

Another embodiment is a system for determining a set of stimulationparameters for an electrical stimulation lead. The system includes adisplay; and a computer processor coupled to the display and configuredand arranged to perform the following actions: receiving a set ofstimulation parameters including at least one electrode for delivery ofstimulation and a stimulation amplitude for each electrode; determining,using the set of stimulation parameters, a first axial stimulation fieldfor neural elements oriented axially with respect to a longitudinal axisof the lead; and outputting the first axial stimulation field forviewing by a user on the display. The actions may also include receivinga modification of the set of stimulation parameters; determining, usingthe modified set of stimulation parameters, a second axial stimulationfield for neural elements oriented axially with respect to alongitudinal axis of the lead; outputting the second axial stimulationfield for viewing by a user on the display; receiving a selection ofeither the set of stimulation parameters or the modified set ofstimulation parameters as a selected set of stimulation parameters; andoutputting the selected set of stimulation parameters to be received byan electrical stimulation device for delivery of electrical stimulationto a patient via an electrical stimulation lead. The system optionallyincludes an implantable lead and an implantable control modulecoupleable to the lead and configured and arranged to receive the set ofstimulation parameters from the computer processor and to deliverelectrical stimulation to a patient using the lead according to the setof stimulation parameters.

Yet another embodiment is a non-transitory computer-readable mediumhaving processor-executable instructions for determining a set ofstimulation parameters, the processor-executable instructions wheninstalled onto a device enable the device to perform actions, including:receiving a set of stimulation parameters including at least oneelectrode for delivery of stimulation and a stimulation amplitude foreach electrode; determining, using the set of stimulation parameters, afirst axial stimulation field for neural elements oriented axially withrespect to a longitudinal axis of the lead; and outputting the firstaxial stimulation field for viewing by a user. The actions may alsoinclude receiving a modification of the set of stimulation parameters;determining, using the modified set of stimulation parameters, a secondaxial stimulation field for neural elements oriented axially withrespect to a longitudinal axis of the lead; outputting the second axialstimulation field for viewing by a user; receiving a selection of eitherthe set of stimulation parameters or the modified set of stimulationparameters as a selected set of stimulation parameters; and outputtingthe selected set of stimulation parameters to be received by anelectrical stimulation device for delivery of electrical stimulation toa patient via an electrical stimulation lead.

A further embodiment is a modification of the methods, systems, andcomputer-readable media described above where, instead of first andsecond axial stimulation fields for neural elements oriented axiallywith respect to a longitudinal axis of the lead, the methods, systems,and computer-readable media determine and output first and secondnon-orthogonal stimulation fields for neural elements orientednon-orthogonally with respect to a longitudinal axis of the lead at aspecified non-orthogonal angle or over a specified range ofnon-orthogonal angles.

In at least some embodiments, determining a first axial ornon-orthogonal stimulation field includes selecting a plurality ofplanes orthogonal to the lead; modeling the neural elements as fixedlength elements that intersect only one of the planes; and determining,for each plane and using the stimulation parameters, which of the fixedlength elements intersecting the plane are activated using thestimulation parameters.

In at least some embodiments, determining a first axial ornon-orthogonal stimulation field includes modeling the neural elementsas extending axially or non-orthogonally relative to the lead; anddetermining, using the stimulation parameters, which of the neuralelements are activated using the stimulation parameters. In at leastsome embodiments, the method, system, or computer-readable mediumsfurther includes determining, by the computer processor, a time sequenceof activation along the neural elements that are activated using thestimulation parameters and outputting, by the computer processor, thefirst axial or non-orthogonal stimulation field indicating differentstates of the first axial or non-orthogonal stimulation field over timebased on the time sequence. In at least some embodiments, the method,system, or computer-readable mediums further includes receiving, by thecomputer processor, a time selection and outputting, by the computerprocessor, the first axial or non-orthogonal stimulation field at thetime selection based on the time sequence.

In at least some embodiments, determining a first axial ornon-orthogonal stimulation field includes modeling the neural elementsas extending axially or non-orthogonally relative to the lead; anddetermining, using the stimulation parameters, which of the neuralelements are activated using the stimulation parameters and at whatpoint along each of the neural elements that that neural element isfirst activated.

In at least some embodiments, the method, system, or computer-readablemediums further includes determining, by the computer processor andusing the set of stimulation parameters, a first transverse stimulationfield for neural elements oriented orthogonal with respect to alongitudinal axis of the lead; and outputting, by the computerprocessor, the first transverse stimulation field for viewing by a user.In at least some embodiments, outputting the first axial ornon-orthogonal stimulation field and outputting the first transversestimulation field includes outputting the first axial or non-orthogonalstimulation field and first transverse stimulation field simultaneously.In at least some embodiments, the method, system, or computer-readablemediums further includes receiving, by the computer processor, a usercommand to toggle either the first axial or non-orthogonal stimulationfield or first transverse stimulation field either on or off.

In at least some embodiments, receiving a modification of the set ofstimulation parameters includes receiving a modified stimulationamplitude. In at least some embodiments, receiving a modification of theset of stimulation parameters includes receiving a modified selection ofthe at least one electrode for delivery of stimulation.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic side view of one embodiment of a device for brainstimulation, according to the invention;

FIG. 2 is a schematic diagram of radial current steering along variouselectrode levels along the length of a lead, according to the invention;

FIG. 3A is a perspective view of an embodiment of a portion of a leadhaving a plurality of segmented electrodes, according to the invention;

FIG. 3B is a perspective view of a second embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3C is a perspective view of a third embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3D is a perspective view of a fourth embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3E is a perspective view of a fifth embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3F is a perspective view of a sixth embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3G is a perspective view of a seventh embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 3H is a perspective view of an eighth embodiment of a portion of alead having a plurality of segmented electrodes, according to theinvention;

FIG. 4 is a schematic flowchart of one embodiment of a method ofdetermining a set of stimulation parameters, according to the invention;

FIG. 5 is a schematic flowchart of another embodiment of a method ofdetermining a set of stimulation parameters, according to the invention;

FIG. 6A is a schematic illustration of one embodiment of a model fordetermining a stimulation field for neural elements arranged parallel tothe lead, according to the invention;

FIG. 6B is a schematic illustration of the stimulation field for themodel of FIG. 6A, according to the invention;

FIG. 7A is a schematic illustration of one embodiment of another modelfor determining a stimulation field for neural elements arrangedparallel to the lead, according to the invention;

FIG. 7B is a schematic illustration of the stimulation field for themodel of FIG. 7A, according to the invention;

FIG. 8 is a schematic illustration of the stimulation field for themodel of FIG. 7A showing the propagation of the stimulation field overtime, according to the invention;

FIG. 9A is a schematic illustration of one embodiment of a third modelfor determining a stimulation field for neural elements arrangedparallel to the lead, according to the invention;

FIG. 9B is a schematic illustration of the stimulation field for themodel of FIG. 9A, according to the invention; and

FIG. 10 is a schematic illustration of one embodiment of a system forpracticing the invention.

DETAILED DESCRIPTION

The invention is directed to the field of electrical stimulationsystems. The present invention is also directed to systems and methodsfor visualizing and directing electrical stimulation of neural elements,as well as methods of making and using systems.

A lead for electrical stimulation can includes one or more stimulationelectrodes. In at least some embodiments, one or more of the stimulationelectrodes are provided in the form of segmented electrodes that extendonly partially around the circumference of the lead. These segmentedelectrodes can be provided in sets of electrodes, with each set havingelectrodes radially distributed about the lead at a particularlongitudinal position. For illustrative purposes, the leads aredescribed herein relative to use for deep brain stimulation, but it willbe understood that any of the leads can be used for applications otherthan deep brain stimulation, including spinal cord stimulation,peripheral nerve stimulation, dorsal root ganglia stimulation, vagalnerve stimulation, basoreceptor stimulation, or stimulation of othernerves, organs, or tissues.

Suitable implantable electrical stimulation systems include, but are notlimited to, at least one lead with one or more electrodes disposed on adistal end of the lead and one or more terminals disposed on one or moreproximal ends of the lead. Leads include, for example, percutaneousleads. Examples of electrical stimulation systems with leads are foundin, for example, U.S. Pat. Nos. 6,181,969; 6,516,227; 6,609,029;6,609,032; 6,741,892; 7,244,150; 7,450,997; 7,672,734;7,761,165;7,783,359; 7,792,590; 7,809,446; 7,949,395; 7,974,706; 8,175,710;8,224,450; 8,271,094; 8,295,944; 8,364,278; 8,391,985; and 8,688,235;and U.S. Patent Applications Publication Nos. 2007/0150036;2009/0187222; 2009/0276021; 2010/0076535; 2010/0268298; 2011/0005069;2011/0004267; 2011/0078900; 2011/0130817; 2011/0130818; 2011/0238129;2011/0313500; 2012/0016378; 2012/0046710; 2012/0071949; 2012/0165911;2012/0197375; 2012/0203316; 2012/0203320; 2012/0203321; 2012/0316615;2013/0105071; and 2013/0197602, all of which are incorporated byreference.

In at least some embodiments, a practitioner may determine the positionof the target neurons using recording electrode(s) and then position thestimulation electrode(s) accordingly. In some embodiments, the sameelectrodes can be used for both recording and stimulation. In someembodiments, separate leads can be used; one with recording electrodeswhich identify target neurons, and a second lead with stimulationelectrodes that replaces the first after target neuron identification.In some embodiments, the same lead can include both recording electrodesand stimulation electrodes or electrodes can be used for both recordingand stimulation.

FIG. 1 illustrates one embodiment of a device 100 for electricalstimulation (for example, brain or spinal cord stimulation). The deviceincludes a lead 110, a plurality of electrodes 125 disposed at leastpartially about a circumference of the lead 110, a plurality ofterminals 135, a connector 132 for connection of the electrodes to acontrol module, and a stylet 140 for assisting in insertion andpositioning of the lead in the patient's brain. The stylet 140 can bemade of a rigid material. Examples of suitable materials for the styletinclude, but are not limited to, tungsten, stainless steel, and plastic.The stylet 140 may have a handle 150 to assist insertion into the lead110, as well as rotation of the stylet 140 and lead 110. The connector132 fits over a proximal end of the lead 110, preferably after removalof the stylet 140. The connector 132 can be part of a control module orcan be part of an optional lead extension that is coupled to the controlmodule.

The control module (for example, control module 1014 of FIG. 10) can bean implantable pulse generator that can be implanted into a patient'sbody, for example, below the patient's clavicle area. The control modulecan have eight stimulation channels which may be independentlyprogrammable to control the magnitude of the current stimulus from eachchannel. In some cases, the control module can have more or fewer thaneight stimulation channels (e.g., 4-, 6-, 16-, 32-, or more stimulationchannels). The control module can have one, two, three, four, or moreconnector ports, for receiving the plurality of terminals 135 at theproximal end of the lead 110. Examples of control modules are describedin the references cited above.

In one example of operation, access to the desired position in the braincan be accomplished by drilling a hole in the patient's skull or craniumwith a cranial drill (commonly referred to as a burr), and coagulatingand incising the dura mater, or brain covering. The lead 110 can beinserted into the cranium and brain tissue with the assistance of thestylet 140. The lead 110 can be guided to the target location within thebrain using, for example, a stereotactic frame and a microdrive motorsystem. In some embodiments, the microdrive motor system can be fully orpartially automatic. The microdrive motor system may be configured toperform one or more the following actions (alone or in combination):insert the lead 110, retract the lead 110, or rotate the lead 110.

In some embodiments, measurement devices coupled to the muscles or othertissues stimulated by the target neurons, or a unit responsive to thepatient or clinician, can be coupled to the control module or microdrivemotor system. The measurement device, user, or clinician can indicate aresponse by the target muscles or other tissues to the stimulation orrecording electrode(s) to further identify the target neurons andfacilitate positioning of the stimulation electrode(s). For example, ifthe target neurons are directed to a muscle experiencing tremors, ameasurement device can be used to observe the muscle and indicatechanges in tremor frequency or amplitude in response to stimulation ofneurons. Alternatively, the patient or clinician can observe the muscleand provide feedback.

The lead 110 for deep brain stimulation can include stimulationelectrodes, recording electrodes, or both. In at least some embodiments,the lead 110 is rotatable so that the stimulation electrodes can bealigned with the target neurons after the neurons have been locatedusing the recording electrodes.

Stimulation electrodes may be disposed on the circumference of the lead110 to stimulate the target neurons. Stimulation electrodes may bering-shaped so that current projects from each electrode equally inevery direction from the position of the electrode along a length of thelead 110. Ring electrodes typically do not enable stimulus current to bedirected from only a limited angular range around of the lead. Segmentedelectrodes, however, can be used to direct stimulation energy to aselected angular range around the lead. When segmented electrodes areused in conjunction with an implantable control module that deliversconstant current stimulus, current steering can be achieved to moreprecisely deliver the stimulus to a position around an axis of the lead(i.e., radial positioning around the axis of the lead).

To achieve current steering, segmented electrodes can be utilized inaddition to, or as an alternative to, ring electrodes. Though thefollowing description discusses stimulation electrodes, it will beunderstood that all configurations of the stimulation electrodesdiscussed may be utilized in arranging recording electrodes as well. Alead that includes segmented electrodes can be referred to as adirectional lead because the segmented electrodes can be used to directstimulation along a particular direction or range of directions.

The lead 100 includes a lead body 110, one or more optional ringelectrodes 120, and a plurality of sets of segmented electrodes 130. Thelead body 110 can be formed of a biocompatible, non-conducting materialsuch as, for example, a polymeric material. Suitable polymeric materialsinclude, but are not limited to, silicone, polyurethane, polyurea,polyurethane-urea, polyethylene, or the like. Once implanted in thebody, the lead 100 may be in contact with body tissue for extendedperiods of time. In at least some embodiments, the lead 100 has across-sectional diameter of no more than 1.5 mm and may be in the rangeof 0.5 to 1.5 mm. In at least some embodiments, the lead 100 has alength of at least 10 cm and the length of the lead 100 may be in therange of 10 to 70 cm.

The electrodes can be made using a metal, alloy, conductive oxide, orany other suitable conductive biocompatible material. Examples ofsuitable materials include, but are not limited to, platinum, platinumiridium alloy, iridium, titanium, tungsten, palladium, palladiumrhodium, or the like. Preferably, the electrodes are made of a materialthat is biocompatible and does not substantially corrode under expectedoperating conditions in the operating environment for the expectedduration of use.

Each of the electrodes can either be used or unused (OFF). When theelectrode is used, the electrode can be used as an anode or cathode andcarry anodic or cathodic current. In some instances, an electrode mightbe an anode for a period of time and a cathode for a period of time.

Stimulation electrodes in the form of ring electrodes 120 can bedisposed on any part of the lead body 110, usually near a distal end ofthe lead 100. In FIG. 1, the lead 100 includes two ring electrodes 120.Any number of ring electrodes 120 can be disposed along the length ofthe lead body 110 including, for example, one, two three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, sixteen or more ring electrodes 120. It will be understood thatany number of ring electrodes can be disposed along the length of thelead body 110. In some embodiments, the ring electrodes 120 aresubstantially cylindrical and wrap around the entire circumference ofthe lead body 110. In some embodiments, the outer diameters of the ringelectrodes 120 are substantially equal to the outer diameter of the leadbody 110. The length of the ring electrodes 120 may vary according tothe desired treatment and the location of the target neurons. In someembodiments the length of the ring electrodes 120 are less than or equalto the diameters of the ring electrodes 120. In other embodiments, thelengths of the ring electrodes 120 are greater than the diameters of thering electrodes 120. The distal-most ring electrode 120 may be a tipelectrode (see, e.g., tip electrode 320 a of FIG. 3E) which covers most,or all, of the distal tip of the lead.

Deep brain stimulation leads may include one or more sets of segmentedelectrodes. Segmented electrodes may provide for superior currentsteering than ring electrodes because target structures in deep brainstimulation are not typically symmetric about the axis of the distalelectrode array. Instead, a target may be located on one side of a planerunning through the axis of the lead. Through the use of a radiallysegmented electrode array, current steering can be performed not onlyalong a length of the lead but also around a circumference of the lead.This provides precise three-dimensional targeting and delivery of thecurrent stimulus to neural target tissue, while potentially avoidingstimulation of other tissue. Examples of leads with segmented electrodesinclude U.S. Patent Applications Publication Nos. 2010/0268298;2011/0005069; 2011/0078900; 2011/0130803; 2011/0130816; 2011/0130817;2011/0130818; 2011/0078900; 2011/0238129; 2011/0313500; 2012/0016378;2012/0046710; 2012/0071949; 2012/0165911; 2012/197375; 2012/0203316;2012/0203320; 2012/0203321; 2013/0197602; 2013/0261684; 2013/0325091;2013/0317587; 2014/0039587; 2014/0353001; 2014/0358209; 2014/0358210;2015/0018915; 2015/0021817; 2015/0045864; 2015/0021817; 2015/0066120;2013/0197424; 2015/0151113; 2014/0358207; and U.S. Pat. No. 8,483,237,all of which are incorporated herein by reference in their entireties.Examples of leads with tip electrodes include at least some of thepreviously cited references, as well as U.S. Patent ApplicationsPublication Nos. 2014/0296953 and 2014/0343647, all of which areincorporated herein by reference in their entireties.

The lead 100 is shown having a plurality of segmented electrodes 130.Any number of segmented electrodes 130 may be disposed on the lead body110 including, for example, one, two three, four, five, six, seven,eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteenor more segmented electrodes 130. It will be understood that any numberof segmented electrodes 130 may be disposed along the length of the leadbody 110. A segmented electrode 130 typically extends only 75%, 67%,60%, 50%, 40%, 33%, 25%, 20%, 17%, 15%, or less around the circumferenceof the lead.

The segmented electrodes 130 may be grouped into sets of segmentedelectrodes, where each set is disposed around a circumference of thelead 100 at a particular longitudinal portion of the lead 100. The lead100 may have any number segmented electrodes 130 in a given set ofsegmented electrodes. The lead 100 may have one, two, three, four, five,six, seven, eight, or more segmented electrodes 130 in a given set. Inat least some embodiments, each set of segmented electrodes 130 of thelead 100 contains the same number of segmented electrodes 130. Thesegmented electrodes 130 disposed on the lead 100 may include adifferent number of electrodes than at least one other set of segmentedelectrodes 130 disposed on the lead 100.

The segmented electrodes 130 may vary in size and shape. In someembodiments, the segmented electrodes 130 are all of the same size,shape, diameter, width or area or any combination thereof. In someembodiments, the segmented electrodes 130 of each circumferential set(or even all segmented electrodes disposed on the lead 100) may beidentical in size and shape.

Each set of segmented electrodes 130 may be disposed around thecircumference of the lead body 110 to form a substantially cylindricalshape around the lead body 110. The spacing between individualelectrodes of a given set of the segmented electrodes may be the same,or different from, the spacing between individual electrodes of anotherset of segmented electrodes on the lead 100. In at least someembodiments, equal spaces, gaps or cutouts are disposed between eachsegmented electrode 130 around the circumference of the lead body 110.In other embodiments, the spaces, gaps or cutouts between the segmentedelectrodes 130 may differ in size or shape. In other embodiments, thespaces, gaps, or cutouts between segmented electrodes 130 may be uniformfor a particular set of the segmented electrodes 130, or for all sets ofthe segmented electrodes 130. The sets of segmented electrodes 130 maybe positioned in irregular or regular intervals along a length the leadbody 110.

Conductor wires that attach to the ring electrodes 120 or segmentedelectrodes 130 extend along the lead body 110. These conductor wires mayextend through the material of the lead 100 or along one or more lumensdefined by the lead 100, or both. The conductor wires couple theelectrodes 120, 130 to the terminals 135.

When the lead 100 includes both ring electrodes 120 and segmentedelectrodes 130, the ring electrodes 120 and the segmented electrodes 130may be arranged in any suitable configuration. For example, when thelead 100 includes two ring electrodes 120 and two sets of segmentedelectrodes 130, the ring electrodes 120 can flank the two sets ofsegmented electrodes 130 (see e.g., FIGS. 1, 3A, and 3E-3H—ringelectrodes 320 and segmented electrode 330). Alternately, the two setsof ring electrodes 120 can be disposed proximal to the two sets ofsegmented electrodes 130 (see e.g., FIG. 3C—ring electrodes 320 andsegmented electrode 330), or the two sets of ring electrodes 120 can bedisposed distal to the two sets of segmented electrodes 130 (see e.g.,FIG. 3D—ring electrodes 320 and segmented electrode 330). One of thering electrodes can be a tip electrode (see, tip electrode 320 a ofFIGS. 3E and 3G). It will be understood that other configurations arepossible as well (e.g., alternating ring and segmented electrodes, orthe like).

By varying the location of the segmented electrodes 130, differentcoverage of the target neurons may be selected. For example, theelectrode arrangement of FIG. 3C may be useful if the physiciananticipates that the neural target will be closer to a distal tip of thelead body 110, while the electrode arrangement of FIG. 3D may be usefulif the physician anticipates that the neural target will be closer to aproximal end of the lead body 110.

Any combination of ring electrodes 120 and segmented electrodes 130 maybe disposed on the lead 100. For example, the lead may include a firstring electrode 120, two sets of segmented electrodes; each set formed offour segmented electrodes 130, and a final ring electrode 120 at the endof the lead. This configuration may simply be referred to as a 1-4-4-1configuration (FIGS. 3A and 3E—ring electrodes 320 and segmentedelectrode 330). It may be useful to refer to the electrodes with thisshorthand notation. Thus, the embodiment of FIG. 3C may be referred toas a 1-1-4-4 configuration, while the embodiment of FIG. 3D may bereferred to as a 4-4-1-1 configuration. The embodiments of FIGS. 3F, 3G,and 3H can be referred to as a 1-3-3-1 configuration. Other electrodeconfigurations include, for example, a 2-2-2-2 configuration, where foursets of segmented electrodes are disposed on the lead, and a 4-4configuration, where two sets of segmented electrodes, each having foursegmented electrodes 130 are disposed on the lead. The 1-3-3-1 electrodeconfiguration of FIGS. 3F, 3G, and 3H has two sets of segmentedelectrodes, each set containing three electrodes disposed around thecircumference of the lead, flanked by two ring electrodes (FIGS. 3F and3H) or a ring electrode and a tip electrode (FIG. 3G). In someembodiments, the lead includes 16 electrodes. Possible configurationsfor a 16-electrode lead include, but are not limited to 4-4-4-4; 8-8;3-3-3-3-3-1 (and all rearrangements of this configuration); and2-2-2-2-2-2-2-2.

FIG. 2 is a schematic diagram to illustrate radial current steeringalong various electrode levels along the length of the lead 200. Whileconventional lead configurations with ring electrodes are only able tosteer current along the length of the lead (the z-axis), the segmentedelectrode configuration is capable of steering current in the x-axis,y-axis as well as the z-axis. Thus, the centroid of stimulation may besteered in any direction in the three-dimensional space surrounding thelead 200. In some embodiments, the radial distance, r, and the angle θaround the circumference of the lead 200 may be dictated by thepercentage of anodic current (recognizing that stimulation predominantlyoccurs near the cathode, although strong anodes may cause stimulation aswell) introduced to each electrode. In at least some embodiments, theconfiguration of anodes and cathodes along the segmented electrodesallows the centroid of stimulation to be shifted to a variety ofdifferent locations along the lead 200.

As can be appreciated from FIG. 2, the stimulation can be shifted ateach level along the length L of the lead 200. The use of multiple setsof segmented electrodes at different levels along the length of the leadallows for three-dimensional current steering. In some embodiments, thesets of segmented electrodes are shifted collectively (i.e., thecentroid of simulation is similar at each level along the length of thelead). In at least some other embodiments, each set of segmentedelectrodes is controlled independently. Each set of segmented electrodesmay contain two, three, four, five, six, seven, eight or more segmentedelectrodes. It will be understood that different stimulation profilesmay be produced by varying the number of segmented electrodes at eachlevel. For example, when each set of segmented electrodes includes onlytwo segmented electrodes, uniformly distributed gaps (inability tostimulate selectively) may be formed in the stimulation profile. In someembodiments, at least three segmented electrodes in a set are utilizedto allow for true 360° selectivity.

Turning to FIGS. 3A-3H, when the lead 300 includes a plurality of setsof segmented electrodes 330, it may be desirable to form the lead 300such that corresponding electrodes of different sets of segmentedelectrodes 330 are radially aligned with one another along the length ofthe lead 300 (see e.g., the segmented electrodes 330 shown in FIGS. 3Aand 3C-3G). Radial alignment between corresponding electrodes ofdifferent sets of segmented electrodes 330 along the length of the lead300 may reduce uncertainty as to the location or orientation betweencorresponding segmented electrodes of different sets of segmentedelectrodes. Accordingly, it may be beneficial to form electrode arrayssuch that corresponding electrodes of different sets of segmentedelectrodes along the length of the lead 300 are radially aligned withone another and do not radially shift in relation to one another duringmanufacturing of the lead 300.

In other embodiments, individual electrodes in the two sets of segmentedelectrodes 330 are staggered (see, FIG. 3H) relative to one anotheralong the length of the lead body 310. In some cases, the staggeredpositioning of corresponding electrodes of different sets of segmentedelectrodes along the length of the lead 300 may be designed for aspecific application.

Segmented electrodes can be used to tailor the stimulation region sothat, instead of stimulating tissue around the circumference of the leadas would be achieved using a ring electrode, the stimulation region canbe directionally targeted. In some instances, it is desirable to targeta parallelepiped (or slab) region 250 that contains the electrodes ofthe lead 200, as illustrated in FIG. 2. One arrangement for directing astimulation field into a parallelepiped region uses segmented electrodesdisposed on opposite sides of a lead.

FIGS. 3A-3H illustrate leads 300 with segmented electrodes 330, optionalring electrodes 320 or tip electrodes 320 a, and a lead body 310. Thesets of segmented electrodes 330 each include either two (FIG. 3B),three (FIGS. 3E-3H), or four (FIGS. 3A, 3C, and 3D) or any other numberof segmented electrodes including, for example, three, five, six, ormore. The sets of segmented electrodes 330 can be aligned with eachother (FIGS. 3A-3G) or staggered (FIG. 3H)

Any other suitable arrangements of segmented electrodes can be used. Asan example, arrangements in which segmented electrodes are arrangedhelically with respect to each other. One embodiment includes a doublehelix.

In at least some instances, a treating physician may wish to tailor thestimulation parameters (such as which one or more of the stimulatingelectrode contacts to use, the stimulation pulse amplitude (such ascurrent or voltage amplitude depending on the stimulator being used,)the stimulation pulse width, the stimulation frequency, or the like orany combination thereof) for a particular patient to improve theeffectiveness of the therapy. Electrical stimulation systems can providean interface that facilitates parameter selections. Examples of suchsystems and interfaces can be found in, for example, U.S. patentapplications Ser. Nos. 12/454,330; 12/454,312; 12/454,340; 12/454,343;and 12/454,314 and U.S. Patent Application Publication No. 2014/0277284,all of which are incorporated herein by reference in their entireties.

Conventional electrical stimulation (such as deep brain or spinal cordstimulation) can include a programming procedure that is often performedin an initial session and, in at least some instances, at latersessions. The procedure can involve, for example, testing different setsof stimulation parameters (which can include variations in theelectrodes that are selected as well as different electrical parameterssuch as amplitude, duration, pulse frequency, and the like) andannotating when there is a beneficial therapeutic effect or an unwantedside effect. In at least some embodiments, the clinician performs amonopolar review testing each electrode individually and recordingtherapeutic/beneficial effects and side effects for each electrode onthe lead corresponding to different values of the stimulation amplitudeor other stimulation parameters. The clinician may also perform bipolaror multipolar reviews using two or more electrodes.

In contrast to these conventional methods, stimulation regionvisualization systems and methods can be used to predict or estimate aregion of stimulation for a given set of stimulation parameters. In atleast some embodiments, the systems and methods further permit a user tomodify stimulation parameters and visually observe how suchmodifications can change the predicted or estimated stimulation region.Such algorithms and systems may provide greater ease of use andflexibility and may enable or enhance stimulation therapy. The terms“stimulation field map” (SFM) and “volume of activation” (VOA) are oftenused to designate an estimated region of tissue that will be stimulatedfor a particular set of stimulation parameters. Any suitable method fordetermining the VOA/SFM can be used including those described in, forexample, U.S. Pat. Nos. 8,326,433; 8,675,945; 8,831,731; 8,849,632; and8,958,615; U.S. Patent Application Publications Nos. 2009/0287272;2009/0287273; 2012/0314924; 2013/0116744; 2014/0122379; and2015/0066111; and U.S. Provisional Patent Application Ser. No.62/030,655, all of which are incorporated herein by reference.

Neural elements (e.g., neural fibers, axons, or the like) can bearranged at any angle with respect to the lead including, but notlimited to, both perpendicular or parallel to the longitudinal axis ofthe lead. At least some visualization methods and systems only determinethe activation of neural elements that are transverse (i.e.,perpendicular or orthogonal) to the longitudinal axis of the lead.Neural elements, such as axons or presynaptic terminals, are referred toin the discussion below, but it will be recognized that other anatomicfeatures, such as cell bodies or the like can be featured in place ofthe neural elements.

One example of an activating function that can be employed toapproximate the neural element response to electrical stimulation is asecond difference of the extracellular potential distribution along aneural element (for example, ∂²V/∂x² or approximations of this quantityfor neural elements such as axons), where V represents the potentialalong the neural element and x represents a position along the neuralelement. The second difference provides a quantitative estimate of thepolarization of the axon in response to an applied electric field.Another example of a neural element is a presynaptic terminal wherelikelihood of activation, at least in some instances, is proportional to∂V/∂x (e.g., the first derivative of voltage along a direction ofpropagation in the parent axon) or approximations of this quantity.Combinations of these two quantities or other parameters may be used aswell.

The methods and systems described herein, however, are directed todetermining the stimulation region for neural elements that are arrangedparallel to the longitudinal axis of the lead or at a non-orthogonalangle (for example, an angle less than 90 degrees or an angle in a rangeof 0 to 80 degrees or 0 to 75 degrees or 0 to 45 degrees or 45 to 80degrees) relative to the longitudinal axis. In particular, in at leastsome embodiments, the present methods and systems utilize one of severalmodels to represent such neural elements.

FIG. 4 illustrates one embodiment of a method for determining an axialstimulation field and for providing stimulation parameters to astimulation device to treat a patient. In step 402, a set of stimulationparameters is received. Examples of stimulation parameters that can bereceived include, but are not limited to, selection of one or moreelectrodes of a lead to provide the stimulation, a stimulation amplitudefor each of the selected electrodes (or a total stimulation amplitude oruniform stimulation amplitude), pulse duration, pulse width, pulsepattern, and the like. In at least some embodiments, the set ofstimulation parameters include an identification of at least oneelectrode for stimulation and a stimulation amplitude for each of theelectrodes. The stimulation amplitude may also indicate the polarity ofthe electrode (e.g., whether the electrode is an anode or cathode) tothe polarity may be provided separately. The set of stimulationparameters can be received from a user, such as a clinician or patient;or can be generated by, for example, an electrical stimulation system,clinician programmer, patient programmer, or other device; or can bereceived from a database or other source of stimulation parameters. Anyother suitable method or arrangement for receiving the set ofstimulation parameters can also be used.

In step 404, an axial stimulation field is determined. The axialstimulation field is the region around the electrodes where axiallyoriented neural elements (i.e., neural elements oriented parallel to thelongitudinal axis of the lead) are activated using the receivedstimulation parameters. A number of models for the axially orientedneural elements are presented below to facilitate the determination. Inaddition, any suitable method can be used for determining the potentialor electrical field generated around the lead using the receivedstimulation parameters. The selected model and the determined potentialor electrical field can then be used to determine the region in whichaxially oriented neural elements will be activated using the receivedstimulation parameters. For example, the stimulation field can bedetermined using SFM or VOA techniques. Alternatively or additionally, astimulation field for neural elements at another non-orthogonal angle ora range of angles can be determined; in which case, reference to the“axial stimulation field” in the description of the remainder of thesteps should be replace with this determined stimulation field.

In step 406, the axial stimulation field is output for viewing by theuser. For example, the axial stimulation field can be displayed with amodel of the distal portion of the lead. In at least some embodiments,the electrode(s) that are to be used for stimulation (or all of theelectrodes) are also displayed on the model. As described in more detailbelow, the display may also include at least some of the stimulationparameters and may also include controls for changing one or more of thestimulation parameters or for modifying the axial stimulation field. Inaddition, as described in more detail below, the display may alsodisplay a transverse stimulation field that is determined, using thestimulation parameters, for neural elements oriented transversely (e.g.,perpendicularly) to the longitudinal axis of the lead. Alternatively oradditionally, the display may also display one or more non-orthogonalstimulation fields for neural elements oriented at one or more differentnon-orthogonal angles (or angle ranges) relative to the longitudinalaxis of the lead.

In optional step 408, the user may select the stimulation parameters forstimulating a patient. In optional step 410, those stimulationparameters may be output to a stimulation device, such as the controlmodule described above, using, for example, wired or wirelesscommunication. In optional step 412, the stimulation device canstimulate the patient using an attached lead with electrodes and theselected stimulation parameters.

FIG. 5 illustrates another embodiment of a method for determining anaxial stimulation field and for providing stimulation parameters to astimulation device to treat a patient. In step 502, a set of stimulationparameters is received. Examples of stimulation parameters that can bereceived include, but are not limited to, selection of one or moreelectrodes of a lead to provide the stimulation, a stimulation amplitudefor each of the selected electrodes (or a total stimulation amplitude oruniform stimulation amplitude), pulse duration, pulse width, pulsepattern, and the like. In at least some embodiments, the set ofstimulation parameters include an identification of at least oneelectrode for stimulation and a stimulation amplitude for each of theelectrodes. The stimulation amplitude may also indicate the polarity ofthe electrode (e.g., whether the electrode is an anode or cathode) tothe polarity may be provided separately. The set of stimulationparameters can be received from a user, such as a clinician or patient;or can be generated by, for example, an electrical stimulation system,clinician programmer, patient programmer, or other device; or can bereceived from a database or other source of stimulation parameters. Anyother suitable method or arrangement for receiving the set ofstimulation parameters can also be used.

In step 504, a first axial stimulation field is determined. The firstaxial stimulation field is the region around the electrodes whereaxially oriented neural elements (i.e., neural elements orientedparallel to the longitudinal axis of the lead) are activated using thereceived stimulation parameters. A number of models for the axiallyoriented neural elements are presented below to facilitate thedetermination. In addition, any suitable method can be used fordetermining the potential or electrical field generated around the leadusing the received stimulation parameters. The selected model and thedetermined potential or electrical field can then be used to determinethe region in which axially oriented neural elements will be activatedusing the received stimulation parameters. Alternatively oradditionally, a first stimulation field for neural elements at anothernon-orthogonal angle or a range of angles can be determined; in whichcase, reference to the “first axial stimulation field” in thedescription of the remainder of the steps should be replace with thisdetermined first stimulation field.

Optionally, in step 504, the first axial stimulation field is output forviewing by the user. For example, the first axial stimulation field canbe displayed with a model of the distal portion of the lead. In at leastsome embodiments, the electrode(s) that are to be used for stimulation(or all of the electrodes) are also displayed on the model. As describedin more detail below, the display may also include at least some of thestimulation parameters and may also include controls for changing one ormore of the stimulation parameters or for modifying the first axialstimulation field. In addition, as described in more detail below, thedisplay may also display a transverse stimulation field that isdetermined, using the stimulation parameters, for neural elementsoriented transversely (e.g., perpendicularly) to the longitudinal axisof the lead. Alternatively or additionally, the display may also displayone or more non-orthogonal stimulation fields for neural elementsoriented at one or more different non-orthogonal angles (or angleranges) relative to the longitudinal axis of the lead.

In step 506, a modification of the stimulation parameters is received.For example, a user may modify one or more of the stimulation parametersthrough a user interface or the system may automatically or, whenrequested, modify one or more of the stimulation parameters. In someembodiments, the user can input a new value for one or more stimulationparameters or may use sliders, buttons (for example, increasing ordecreasing buttons), or other controls on the user interface to modifyor otherwise alter one or more stimulation parameters. For example, theuser may increase or decrease a stimulation amplitude, pulse duration,pulse pattern, or the like or select one or more different electrodesfor providing the stimulation or any other suitable change to thestimulation parameters.

In step 508, a second axial stimulation field is determined using themodified stimulation parameters. Optionally, in step 508, the secondaxial stimulation field is output for viewing by the user. In someembodiments, the second axial stimulation field is displayedsimultaneously with the first axial stimulation field in separatedisplay regions or overlaid in the same display region. Alternatively oradditionally, a second stimulation field for neural elements at anothernon-orthogonal angle or a range of angles can be determined; in whichcase, reference to the “second axial stimulation field” in thedescription of the remainder of the steps should be replace with thisdetermined second stimulation field.

Steps 506 and 508 can be performed multiple times to produce additionalaxial stimulation fields. In optional step 510, the user can select oneof the sets of stimulation parameters. Alternatively, the system canselect set of stimulation parameters automatically based on one or morecriteria, such as, for example, a fit to a target stimulation region. Inoptional step 512, the selected stimulation parameters may be output toa stimulation device, such as the control module described above, using,for example, wired or wireless communication. In optional step 512, thestimulation device can stimulate the patient using an attached lead withelectrodes and the selected stimulation parameters.

It will be understood that the methods described with respect to FIGS. 4and 5 can be performed multiple times to produce multiple axialstimulation fields. In some embodiments, a user may select from amongthe multiple axial stimulation fields and corresponding sets ofstimulation parameters to obtain a set of stimulation parameters tooutput to the stimulation device to stimulate the patient.

In order to determine the axial stimulation field, a model of the axialneural elements is constructed. FIG. 6A illustrates a model of thedistal end of a lead 600 with a stimulating electrode 625. The neuralelements 650 are modeled as short cylinders that are each fixed on oneof multiple slices 652 orthogonal to the lead 600. In some embodiments,the neural elements 650 are centered on the respective slices 652. In atleast some embodiments, each neural element 650 intersects only oneslice 652.

In at least some embodiments, to determine which neural elements 650 areactivated, the stimulation parameters are used to determine the electricfield. The electric field at the region 654 for each neural element 650that intersects the corresponding slice 652 is investigated along theneural element to determine whether that particular neural element isactivated or not. As an example, the second difference of theextracellular potential distribution (for example, ∂²V/∂x², ∂V/∂x, orapproximations or any combinations of these quantities, where Vrepresents the potential along the neural element and x representspositions along the neural element) of the neural element 650 can bedetermined along the neural element and, if it meets or exceeds athreshold value, the neural element 650 is activated; if not, the neuralelement is not activated.

The composite activated neural elements 650 from each slice 652 are thenused to form the axial stimulation field 656, as illustrated in FIG. 6B,where the regions 654 of the neural elements 650 within the axialstimulation field 656 are activated and those outside the axialstimulation field 656 are not activated. FIG. 6B also illustrates oneembodiment of a control 658 (in this case, up and down areas and a boxcontaining the parameter value) for altering a stimulation parameter,such as the stimulation amplitude, pulse width, pulse frequency, or thelike. As described above, when the stimulation parameter is modified,the illustrated axial stimulation field 656 can be updated in view ofthe modified stimulation parameter.

FIG. 7A illustrates the distal end of a lead 700 with a stimulatingelectrode 725. In this embodiment, the neural elements 750 are modeledas long cylinders orthogonal to the lead 700. In at least someembodiments, to determine which neural elements 750 are activated, thestimulation parameters are used to determine the electric field alongneural elements 750. As an example, the second difference of theextracellular potential distribution (for example, ∂²V/∂x², ∂V/∂x, orapproximations or any combinations of these quantities, where Vrepresents the potential along the neural element and x representspositions along the neural element) of the neural element 750 can bedetermined and, if it meets or exceeds a threshold value, the neuralelement 750 is activated; if not, the neural element is not activated.

The composite activated neural elements 750 are then used to form theaxial stimulation field 756, as illustrated in FIG. 7B, where the neuralelements 750 within the axial stimulation field 756 are activated andthose outside the axial stimulation field 756 are not activated. FIG. 7Balso illustrates one embodiment of a control 758 (in this case, up anddown areas and a box containing the parameter value) for altering astimulation parameter, such as the stimulation amplitude, pulse width,pulse frequency, or the like. As described above, when the stimulationparameter is modified, the illustrated axial stimulation field 756 canbe updated in view of the modified stimulation parameter. FIG. 7B alsoillustrates that a transverse stimulation field 760 can be determined,using, for example, conventional SFM or VOA calculations for transverseneural elements, and displayed together with the axial stimulation field756. It will be understood that the transverse stimulation field canalso be determined and displayed for the embodiment illustrated in FIG.6B.

It will be understood that the stimulation fields illustrated in FIGS.6B and 7B are actually two-dimensional cross-sections of the stimulationfields. In other embodiments, an interface may display a representationthat portrays a three-dimensional stimulation field or allow forselection of different two-dimensional cross-sections of the stimulationfield.

In some embodiments, the user interface may also permit the user toswitch between displaying both the axial and transverse stimulationfield; only the axial stimulation field; or only the transversestimulation field. The user interface may also present or allow the userto select a display that is a combination (e.g., union) or intersectionof the axial and transverse stimulation fields. Color, shading, or thelike may be used to distinguish between different stimulation fields. Insome embodiments, the interface may also, or alternatively, display oneor more additional non-orthogonal stimulation fields and, optionally,any combinations or intersections of the displayed or determined axial,transverse, or non-orthogonal stimulation fields.

FIG. 8 illustrates another display that utilizes the model describedwith respect to FIG. 7A and adds a temporal dimension by considering thetime of propagation of the action potential along the neural element 750from the region 754 of initial activation. FIG. 8 illustrates the axialstimulation field at three different times corresponding to axialstimulation fields 856 a, 856 b, 856 c, respectively. In at least someembodiments, the higher the electrical field at the activation region764, the faster the neural element 750 will activate and the actionpotential will propagate. In at least some embodiments, the higher theelectrical field at the activation region 754, the longer the portion ofthe neural element 750 that will be activated. FIG. 8 also illustrates acontrol 862 that may be used to select a time after initiation ofstimulation for display of the corresponding axial propagation field856. In some embodiments, the user interface may also include a controlthat the user can operate to view a time progression of the axialstimulation field 856. In some embodiments, the user interface maypermit the user to select multiple times and the user will display theaxial stimulation fields 856 a, 856 b, 856 c at those different times inthe same display region or different display regions. In someembodiments, the time that can be selected represents the time betweenfiring of adjacent nodes of the neural elements.

FIG. 9A illustrates the distal end of a lead 900 with a stimulatingelectrode 925. In this embodiment, the neural elements 950 are modeledas long cylinders that are orthogonal to the lead 900. In at least someembodiments, to determine which neural elements 950 are activated, thestimulation parameters are used to determine the electric field in theregion adjacent to the lead 900. Each neural element 950 is investigatedto determine at what point that particular neural element is firstactivated, as represented by an “x” 955. As an example, the seconddifference of the extracellular potential distribution (for example,∂²V/∂x², ∂V/∂x, or approximations or any combinations of thesequantities, where V represents the potential along the neural elementand x represents positions along the neural element) of the neuralelement 950 can be determined in the region adjacent the lead 900 and,if it meets or exceeds a threshold value, along that region the neuralelement 950 is activated; if not, the neural element is not activated.In at least some embodiments, the time evolution of the electric field,based on the stimulation parameters, is used to determine the firstpoint 955 at which each neural element 950 is activated.

In at least some embodiments, when an axon is activated, some nodes areactivated by the stimulation pulse, and others are activated by thenormal course of the activation moving along the axon. Analysis of thedifference in the activation times of adjacent nodes can, at least insome instances, produce a determination whether a particular node wasactivated as a direct result of the stimulation pulse, or if it wasactivated by the normal course of activation progressing along the axon.In at least some embodiments, when the times of activation of the nodesare determined, a volume of activation can be constructed by using thenodes for which the time difference in activation shows that theactivation is the result of stimulation. In at least some embodiments,an activation threshold is defined as the amplitude at which the nearestnode fires after the test node has fired with a time difference of lessthan the propagation delay.

The composite activated neural elements 950 are then used to form theaxial stimulation field 956, as illustrated in FIG. 9B, where theregions 954 of the neural elements 950 within the axial stimulationfield 956 are activated and those outside the axial stimulation field956 are not activated. In at least some embodiments, the user interfacemay also include a control for altering a stimulation parameter, such asthe stimulation amplitude, or altering a time during or after thestimulation. As described above, when the stimulation parameter or timeis modified, the illustrated axial stimulation field 956 can be updatedin view of the modified stimulation parameter. In some embodiments, thetime progression of the axial stimulation field can be illustrated asdescribed above with respect to FIG. 8.

The models illustrated above in FIGS. 6A-9B have been described relativeto modeling axial neural elements and axial stimulation fields. It willbe recognized that these same models can be modified usingnon-orthogonal neural elements to determine non-orthogonal stimulationfields.

FIG. 10 illustrates one embodiment of a system for practicing theinvention. The system can include a computer 1000 or any other similardevice that includes a processor 1002 and a memory 1004, a display 1006,an input device 1008, and, optionally, the electrical stimulation system1012.

The computer 1000 can be a laptop computer, desktop computer, tablet,mobile device, smartphone or other devices that can run applications orprograms, or any other suitable device for processing information andfor presenting a user interface (such as the user interfaces of FIGS.5A, 5B, 6A-6C, 9, and 10). The computer can be, for example, a clinicianprogrammer, patient programmer, or remote programmer for the electricalstimulation system 1012. The computer 1000 can be local to the user orcan include components that are non-local to the user including one orboth of the processor 1002 or memory 1004 (or portions thereof). Forexample, in some embodiments, the user may operate a terminal that isconnected to a non-local computer. In other embodiments, the memory canbe non-local to the user.

The computer 1000 can utilize any suitable processor 1002 including oneor more hardware processors that may be local to the user or non-localto the user or other components of the computer. The processor 1002 isconfigured to execute instructions provided to the processor, asdescribed below.

Any suitable memory 1004 can be used for the computer 1002. The memory1004 illustrates a type of computer-readable media, namelycomputer-readable storage media. Computer-readable storage media mayinclude, but is not limited to, nonvolatile, non-transitory, removable,and non-removable media implemented in any method or technology forstorage of information, such as computer readable instructions, datastructures, program modules, or other data. Examples ofcomputer-readable storage media include RAM, ROM, EEPROM, flash memory,or other memory technology, CD-ROM, digital versatile disks (“DVD”) orother optical storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices, or any other medium which canbe used to store the desired information and which can be accessed by acomputer.

Communication methods provide another type of computer readable media;namely communication media. Communication media typically embodiescomputer-readable instructions, data structures, program modules, orother data in a modulated data signal such as a carrier wave, datasignal, or other transport mechanism and include any informationdelivery media. The terms “modulated data signal,” and “carrier-wavesignal” includes a signal that has one or more of its characteristicsset or changed in such a manner as to encode information, instructions,data, and the like, in the signal. By way of example, communicationmedia includes wired media such as twisted pair, coaxial cable, fiberoptics, wave guides, and other wired media and wireless media such asacoustic, RF, infrared, and other wireless media.

The display 1006 can be any suitable display device, such as a monitor,screen, display, or the like, and can include a printer. The inputdevice 1008 can be, for example, a keyboard, mouse, touch screen, trackball, joystick, voice recognition system, or any combination thereof, orthe like and can be used by the user to interact with a user interfaceor clinical effects map.

The electrical stimulation system 1012 can include, for example, acontrol module 1014 (for example, an implantable pulse generator) and alead 1016 (for example, the lead illustrated in FIG. 1.) The electricalstimulation system 1012 may communicate with the computer 1000 through awired or wireless connection or, alternatively or additionally, a usercan provide information between the electrical stimulation system 1012and the computer 1000 using a computer-readable medium or by some othermechanism. In some embodiments, the computer 1000 may include part ofthe electrical stimulation system.

The methods and systems described herein may be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Accordingly, the methods and systemsdescribed herein may take the form of an entirely hardware embodiment,an entirely software embodiment or an embodiment combining software andhardware aspects. Systems referenced herein typically include memory andtypically include methods for communication with other devices includingmobile devices. Methods of communication can include both wired andwireless (e.g., RF, optical, or infrared) communications methods andsuch methods provide another type of computer readable media; namelycommunication media. Wired communication can include communication overa twisted pair, coaxial cable, fiber optics, wave guides, or the like,or any combination thereof. Wireless communication can include RF,infrared, acoustic, near field communication, Bluetooth™, or the like,or any combination thereof.

It will be understood that each block of the flowchart illustrations,and combinations of blocks in the flowchart illustrations and methodsdisclosed herein, can be implemented by computer program instructions.These program instructions may be provided to a processor to produce amachine, such that the instructions, which execute on the processor,create means for implementing the actions specified in the flowchartblock or blocks disclosed herein. The computer program instructions maybe executed by a processor to cause a series of operational steps to beperformed by the processor to produce a computer implemented process.The computer program instructions may also cause at least some of theoperational steps to be performed in parallel. Moreover, some of thesteps may also be performed across more than one processor, such asmight arise in a multi-processor computer system. In addition, one ormore processes may also be performed concurrently with other processes,or even in a different sequence than illustrated without departing fromthe scope or spirit of the invention.

The computer program instructions can be stored on any suitablecomputer-readable medium including, but not limited to, RAM, ROM,EEPROM, flash memory or other memory technology, CD-ROM, digitalversatile disks (“DVD”) or other optical storage, magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,or any other medium which can be used to store the desired informationand which can be accessed by a computer.

The above specification and examples data provide a description of theinvention. Since many embodiments of the invention can be made withoutdeparting from the spirit and scope of the invention, the invention alsoresides in the claims hereinafter appended.

What is claimed as new and desired to be protected by Letters Patent ofthe United States is:
 1. A computer-implemented method for determining aset of stimulation parameters for an electrical stimulation lead, themethod comprising: receiving, by a computer processor, a set ofstimulation parameters comprising at least one electrode for delivery ofstimulation and a stimulation amplitude for each of the at least oneelectrode; determining, by the computer processor and using the set ofstimulation parameters, a first axial stimulation field for neuralelements oriented axially with respect to a longitudinal axis of thelead; outputting, by the computer processor, the first axial stimulationfield for viewing by a user; receiving, by the computer processor, amodification of the set of stimulation parameters; determining, by thecomputer processor and using the modified set of stimulation parameters,a second axial stimulation field for neural elements oriented axiallywith respect to a longitudinal axis of the lead; outputting, by thecomputer processor, the second axial stimulation field for viewing by auser; receiving, by the computer processor, a selection of either theset of stimulation parameters or the modified set of stimulationparameters as a selected set of stimulation parameters; and outputting,by the computer processor, the selected set of stimulation parameters tobe received by an electrical stimulation device for delivery ofelectrical stimulation to a patient via an electrical stimulation lead.2. The method of claim 1, wherein determining a first axial stimulationfield comprises selecting a plurality of planes orthogonal to the lead;modeling the neural elements as fixed length elements that intersectonly one of the planes; and determining, for each plane and using thestimulation parameters, which of the fixed length elements intersectingthe plane are activated using the stimulation parameters.
 3. The methodof claim 1, wherein determining a first axial stimulation fieldcomprises modeling the neural elements as extending axially relative tothe lead; and determining, using the stimulation parameters, which ofthe neural elements are activated using the stimulation parameters. 4.The method of claim 3, further comprising determining, by the computerprocessor, a time sequence of activation along the neural elements thatare activated using the stimulation parameters and outputting, by thecomputer processor, the first axial stimulation field indicatingdifferent states of the first axial stimulation field over time based onthe time sequence.
 5. The method of claim 4, further comprisingreceiving, by the computer processor, a time selection and outputting,by the computer processor, the first axial stimulation field at the timeselection based on the time sequence.
 6. The method of claim 1, whereindetermining a first axial stimulation field comprises modeling theneural elements as extending axially relative to the lead; anddetermining, using the stimulation parameters, which of the neuralelements are activated using the stimulation parameters and at whatpoint along each of the neural elements that that neural element isfirst activated.
 7. The method of claim 1, further comprisingdetermining, by the computer processor and using the set of stimulationparameters, a first transverse stimulation field for neural elementsoriented orthogonal with respect to a longitudinal axis of the lead; andoutputting, by the computer processor, the first transverse stimulationfield for viewing by a user.
 8. The method of claim 7, whereinoutputting the first axial stimulation field and outputting the firsttransverse stimulation field comprises outputting the first axialstimulation field and first transverse stimulation field simultaneously.9. The method of claim 8, further comprising receiving, by the computerprocessor, a user command to toggle either the first axial stimulationfield or first transverse stimulation field either on or off.
 10. Themethod of claim 1, wherein receiving a modification of the set ofstimulation parameters comprises receiving a modified stimulationamplitude.
 11. The method of claim 1, wherein receiving a modificationof the set of stimulation parameters comprises receiving a modifiedselection of the at least one electrode for delivery of stimulation. 12.A system for determining a set of stimulation parameters for anelectrical stimulation lead, the system comprising: a display; and acomputer processor coupled to the display and configured and arranged toperform the method of claim
 16. 13. The system of claim 12, furthercomprising an implantable lead and an implantable control modulecoupleable to the lead and configured and arranged to receive the set ofstimulation parameters from the computer processor and to deliverelectrical stimulation to a patient using the lead according to the setof stimulation parameters.
 14. A non-transitory computer-readable mediumhaving processor-executable instructions for determining a set ofstimulation parameters, the processor-executable instructions wheninstalled onto a device enable the device to perform actions, including:receiving a set of stimulation parameters comprising at least oneelectrode for delivery of stimulation and a stimulation amplitude foreach of the at least one electrode; determining, using the set ofstimulation parameters, a first axial stimulation field for neuralelements oriented axially with respect to a longitudinal axis of thelead; outputting the first axial stimulation field for viewing by auser; receiving a modification of the set of stimulation parameters;determining, using the modified set of stimulation parameters, a secondaxial stimulation field for neural elements oriented axially withrespect to a longitudinal axis of the lead; outputting the second axialstimulation field for viewing by a user; receiving a selection of eitherthe set of stimulation parameters or the modified set of stimulationparameters as a selected set of stimulation parameters; and outputtingthe selected set of stimulation parameters to be received by anelectrical stimulation device for delivery of electrical stimulation toa patient via an electrical stimulation lead.
 15. The non-transitorycomputer-readable medium of claim 14, wherein determining a first axialstimulation field comprises selecting a plurality of planes orthogonalto the lead; modeling the neural elements as fixed length elements thatintersect only one of the planes; and determining, for each plane andusing the stimulation parameters, which of the fixed length elementsintersecting the plane are activated using the stimulation parameters.16. The non-transitory computer-readable medium of claim 14, whereindetermining a first axial stimulation field comprises modeling theneural elements as extending axially relative to the lead; anddetermining, using the stimulation parameters, which of the neuralelements are activated using the stimulation parameters.
 17. Acomputer-implemented method for determining a set of stimulationparameters for an electrical stimulation lead, the method comprising:receiving, by a computer processor, a set of stimulation parameterscomprising at least one electrode for delivery of stimulation and astimulation amplitude for each of the at least one electrode;determining, by the computer processor and using the set of stimulationparameters, a first non-orthogonal stimulation field for neural elementsoriented non-orthogonally with respect to a longitudinal axis of thelead at a specified non-orthogonal angle or over a specified range ofnon-orthogonal angles; outputting, by the computer processor, the firstnon-orthogonal stimulation field for viewing by a user; receiving, bythe computer processor, a modification of the set of stimulationparameters; determining, by the computer processor and using themodified set of stimulation parameters, a second non-orthogonalstimulation field for neural elements oriented non-orthogonally withrespect to a longitudinal axis of the lead; outputting, by the computerprocessor, the second non-orthogonal stimulation field for viewing by auser; receiving, by the computer processor, a selection of either theset of stimulation parameters or the modified set of stimulationparameters as a selected set of stimulation parameters; and outputting,by the computer processor, the selected set of stimulation parameters tobe received by an electrical stimulation device for delivery ofelectrical stimulation to a patient via an electrical stimulation lead.18. The method of claim 17, wherein determining a first non-orthogonalstimulation field comprises selecting a plurality of planes orthogonalto the lead; modeling the neural elements as fixed length elements thatintersect only one of the planes; and determining, for each plane andusing the stimulation parameters, which of the fixed length elementsintersecting the plane are activated using the stimulation parameters.19. The method of claim 17, wherein determining a first non-orthogonalstimulation field comprises modeling the neural elements as extendingnon-orthogonally relative to the lead; and determining, using thestimulation parameters, which of the neural elements are activated usingthe stimulation parameters.
 20. The method of claim 19, furthercomprising determining, by the computer processor, a time sequence ofactivation along the neural elements that are activated using thestimulation parameters and outputting, by the computer processor, thefirst non-orthogonal stimulation field indicating different states ofthe first non-orthogonal stimulation field over time based on the timesequence.